simon60

I know this has been asked a thousand times, but I must ask again. I've done a couple of searches and they send me to a website that is no longer active ( www.c4vettes.com) Can anyone please give me the paper clip method?????

greenvette95

Last year I tried to find a way to read my 95's code, have not been able to. My 91 I could do the paper clip way, does not work on 95. If you do find a way please let me know. Thanks.

95AquaVette

The 91 had OBD-1 where the paper clip method would work. The 95 has OBD-2 the paper clip method does not work on that sytem. The only way to grab codes from OBD-2 is to buy a scanner. I know on the C5's there is a button combonation you can push and the car will display the codes on the DIC but i dont know if the C4's have a way of doing that if I find anything I will post it.

Hooked on Vettes

The 94 and 95 Vette's have an OBDII Diagnostic connector but are not OBDII compliant.

To enter diagnostic mode.
Short pin 12 to pin 4 or 5.

Turn ignition on. Do not start the engine.

Connector located above driver side right knee and pin out looks like below.

01,02,03,04,05,06,07,08
09,10,11,12,13,14,15,16

After turning the ignition on the CCM will display
any Diagnostic Trouble Codes (DTC's) and the module for which they apply in an automatic sequence.

CCM=Module 1
PCM=Module 4
ABS/TCS EBTCM is Module 9
DERM (Airbag) is Module A

Each DTC is displayed for 3 seconds followed by a one second pause before the next DTC is displayed.

There is a three second pause between the DTC display sequence for each module.

The end of the DTC list for each module is indicated by
"----" being displayed in the speedometer.

If there is a communications problem between the CCM and the other modules, "Err" is displayed.

The particular module being interrogated is indicated on the trip monitor, and the DTC's are displayed in the speedometer.

simon60

Outstanding!!!!!!!!!!!!! Thank you for taking the time to help me out! I will try it tomorrow.

skateparkdave

I saved the whole page from c4vettes.com on the code subject to floppy with all the diagrams ect..before they shut down. If you would like it PM me your email and I'd be happy to share it.

Dave

midlifecrisis91

You the Man with the Info!!!!

Atok

Yeah, what he said. I do it all the time on my '95.

FD2BLK

This needs to be a tech tip, I have seen this question posted many times and this is a detailed explination

VFR750

Thanks for putting all of this together so well. I tried it on my 95 and got C 12 for module 1. One of my books ambiguously identifies this as no DTCs, everything normal. Is this correct?

Charlie

Atok

I believe C12 is "No crank sensor signal". Which means your engine was stopped so yes, it's normal.

Hooked on Vettes

CCM DTC C12 is a good sign. It means, On-Board Diagnostics are Operational, and there are no DTC's
(Diagnostic trouble codes) for the CCM (Central Control Module).

For the CCM module, C means the DTC is current.
H means the DTC is no longer present.

For the other modules, the error codes are always displayed as a H (history) code whether they are current or history.

There are some useful things you can do when in diag. mode. An example would be to clear any codes in the CCM or PCM(Powertrain Control Module).

Example to clear CCM error codes.

Ground pin 12 to pin 4 or 5. Turn ignition on and let the display cycle till it completes.

Press Trip/ODO button on the DIC until 1.7 appears in the trip monitor area of the cluster.

Press ENG/MET button on the DIC and hold until "---"
appears in the speedometer area. This will any CCM DTC's.

Turn ignition off then back on and verify no DTC's are present.

To clear any DTC's for the PCM you would do the same thing but use 4.7 instead of 1.7.

When in diag. mode the CCM can also be used to energize different relays such as the Courtesy lamp relay, horn relay, rear defogger relay etc...

The CCM can also display the status of the items that it monitors, such as seat belt switch, high beam
switch, low oil switch, fuel level, Ambient light sensor,
Ignition voltage etc...

So the diagnostics can provide valuable information if you need to trouble shoot a circuit.

All of this information is from the 95 Helms manual.

barefootskier

the info in this thread about touching pin 12 and pin 4 or 5 has been great. the only this missing was a picture or link to a picture of the pin locations in the 16 pin 1995 diagnostic connector. If anyone can help, I need to see if there are any codes before I post a question on my 1995 driveability problem. thanks

Hooked on Vettes

Red Dwarf

This one is still working.

http://www.corvettephotographs.com/c4vettes/index.htm

Richard Church

sfwhy

help i can get to 1.7 then it stops so no 4.series codes ever appear...

steve1657

Thanks all.

antfarmer2

On my 94 I think I used 4&12

Cliff Harris

See these links to extract the error codes:

https://www.corvetteforum.com/forums...post1574918379
http://corvettephotographs.com/c4vettes/codes.htm

This link explains what the various error codes mean from year to year:

https://www.corvetteforum.com/forums...post1576116036